The concept of dynamic entropy (D-entropy), proposed in the mechanics of structured particles is discussed. D-entropy is defined as the relative increase in the internal energy of the system due to its motion energy in the inhomogeneous field of external force. D-entropy is determined completely from the motion equation of the system without any statistical laws. Comparison of D-entropy with thermodynamic entropy of Clausius, Boltzmann's entropy and Kolmogorov -Sinai entropy is performed. The

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... merical results calculations of the changes of the systems' D-entropy consisting from the different numbers of elements during their motions into the non-homogeneous space are given. Areas of application D-entropy and the possibility of its use for the analysis of dynamic systems are discussed.